1. Field of the Invention
The present invention relates to an apparatus, a method, a user terminal apparatus, a program, and a computer readable recording medium for measuring a position of a moving object, and more particularly, to an apparatus, a method, a user terminal apparatus, a program, and a computer readable recording medium for measuring a position of a moving object using a global positioning system (GPS) satellite signal.
2. Description of the Related Art
As a conventional method for measuring a position of a moving object, there are a global positioning system (GPS) scheme for measuring a position of a moving object using a GPS, a triangulation scheme for measuring a position of a moving object using propagation characteristics of radio frequency signals, a cell identification (ID) scheme for tracking a position of a moving object on the basis of a position of a base station, and the like. Among them, the GPS scheme has been known as technology capable of very precisely tracking the position of the moving object at a low cost.
As GPS satellites for measuring the position in this GPS scheme, twenty four GPS satellites orbiting the earth at an altitude of about 20,000 km are used. The GPS satellites use electric waves in a band of 1.5 GHz, a control center called a control station is present on the ground and serves to collect and synchronize information transmitted from the GPS satellites, and users receive signals transmitted from a plurality of GPS satellites through GPS receives to calculate their positions and retain accuracy of positions within several meters in open areas.
Here, as a scheme for measuring the position in the GPS scheme, a triangulation scheme is used as a scheme for measuring the position in the GPS scheme. In this case, at least three satellites are required in order to perform triangulation, and an observation satellite for correcting a time error is required, such that a total of four GPS satellites are required.
In more detail, in the measurement of the position in the GPS scheme, since positions of each of the three satellites are already recognized, distances between the satellites and a GPS receiver are measured to measure the position. Here, a time spent in transferring electric waves may be recognized from a difference from a time in which the electric waves are transmitted from the satellites and a time in which the GPS receiver having a built-in clock receives the electric waves, and the distance from the satellites to the GPS receiver may be calculated by multiplying the time spent in transferring the electric waves by a light velocity.
However, according to the conventional GPS scheme described above, in the case in which reception of the GPS is interrupted due to the surrounding high buildings in a downtown concentrated high rise building area, an internal road of an apartment, or the like, it is impossible to measure the position.
In addition, according to the conventional GPS scheme, even though satellite signals required for measuring the position are received, accuracy of the position is decreased due to an error in the measured position caused by signal noise. Particularly, since the conventional GPS receiver corrects and calculates an average error by calculating all of the received signals, in the case of an invisible area in which the probability that a signal having a large error will be received is high, accuracy of the position is decreased.
In addition, according to the conventional GPS scheme, since a complicated calculation process is included, a high performance arithmetic unit is required in the GPS receiver, and large power is consumed for calculation.